The invention relates to a tracheal tube with a permeation-stable blocking cuff arranged at a shaft.
Such a tracheal tube has been known from DE 39 21 524 A1.
Such tracheal tubes are preferably used with endotracheal anesthesia. After intubation the blocking cuff is in situ filled with air. Then the blocking cuff locks the gap between trachea and the respiration hose in such a way that the inspiration mixture cannot escape anymore and flows into the lungs. Experiments have shown that the pressure of the blocking cuff may increase greatly during intubation anesthesia with certain anesthesia gases, the cause being that during intubation anesthesia the anesthesia gas diffuses into the blocking cuff. This results in a volume change of the gas in the blocking cuff and it presses against the trachea's mucous membrane with an increased pressure. On the one hand, the increase in pressure in the blocking cuff may result in damages of the tracheal wall and, on the other, the blocking cuff may deform in addition plastically in the case of pressures which are too great. If the plastical deformation occurs on the side of the blocking cuff which faces the tube's tip, this may even result in a partial or total lumen displacement of the tube's shaft in the area of the tube's tip.
The changes in volume and thus related changes in pressure within the blocking cuff depend on the concentration difference of the anesthesia gas to the blocking cuff, on the acting time of the anesthesia gas on the blocking cuff and the degree of the blocking cuff's permeability to gas, among other things.
The known tracheal tube provides a low-pressure blocking cuff designed in a multi-layer way with a great surface having relatively thin walls. The volume of the cuff is pre-determined and the blocking cuff can develop in situ without a considerable increase in pressure. The blocking cuff is not permeable to anesthesia gases because it has at least one material layer, for example a metal foil, which is not permeable to anesthesia gas. The materials used with the known blocking cuff have to be well-adapted to each other such that they lie form-fittingly against each other without that pressure is exerted as well as in the state when pressure is exerted, in order to prevent undesired folds. Moreover, in the transitional areas to the shaft a very careful material joint has to be provided, in order that here preferably diffusion areas are prevented.